add peer blob store, which gets blobs from a peer

peer/store.go

@@ -0,0 +1,52 @@
+package peer
+
+import (
+	"github.com/lbryio/lbry.go/extras/errors"
+)
+
+// Store is a blob store that gets blobs from a peer.
+// It satisfies the store.BlobStore interface but cannot put or delete blobs.
+type Store struct {
+	client  *Client
+	connErr error
+}
+
+// NewStore makes a new peer store.
+func NewStore(clientAddress string) *Store {
+	c := &Client{}
+	err := c.Connect(clientAddress)
+	return &Store{client: c, connErr: err}
+}
+
+// Has asks the peer if they have a hash
+func (p *Store) Has(hash string) (bool, error) {
+	if p.connErr != nil {
+		return false, errors.Prefix("connection error", p.connErr)
+	}
+
+	return p.client.HasBlob(hash)
+}
+
+// Get downloads the blob from the peer
+func (p *Store) Get(hash string) ([]byte, error) {
+	if p.connErr != nil {
+		return nil, errors.Prefix("connection error", p.connErr)
+	}
+
+	return p.client.GetBlob(hash)
+}
+
+// Put is not supported
+func (p *Store) Put(hash string, blob []byte) error {
+	panic("PeerStore cannot put or delete blobs")
+}
+
+// PutSD is not supported
+func (p *Store) PutSD(hash string, blob []byte) error {
+	panic("PeerStore cannot put or delete blobs")
+}
+
+// Delete is not supported
+func (p *Store) Delete(hash string) error {
+	panic("PeerStore cannot put or delete blobs")
+}